Cookies with walnuts

These cookies are perfect for morning tea. If we don't manage to use all the dough, we can keep it cold. The cookies will be more tender and more aromatic.
ingredients:
200 g unt (it can be replaced with margarine or lard);
8 ling poison powder;
1 or;
1 packet of baking powder;
1 packet of vanilla sugar;
Rum essence;
Grated lemon peel;
3 sex smantana;
100 g walnuts;
Flour as much as it contains.

The butter, at room temperature, rub the foam with powdered sugar and vanilla sugar. Add the yolk, sour cream, rum essence, grated lemon peel, flour and baking powder.
dough, not to be tall, a roll is made, leave it in the refrigerator until it hardens. After, balls are made the size of a walnut, which is half softened in the egg white rubbed by two, three times, with a fork, and then in the crushed walnuts mixed with powdered sugar. It is placed in an ungreased tray, with the non-soaked side in white.
They cook at the right temperature. Remove from the pan and let cool.
The dough becomes more tender if it is prepared the day before and kept in the refrigerator.